Method for copying indicia by particle transfer



P 1960 I w. H. VANDER WEEL 2,954,311

METHOD FOR COPYING INDICIA VBY PARTICLE TRANSFER Filed Sept. 25, 1957 2Sheets-Sheet 1 FIG.

F/G'. Z 1 5 7 F 1 1 1 1 1 1 1 j 8 F/G. 3 7 I W V V V V 8 5 6 I P76. 4 (71 1 1 1 1 1 8, 1 /2 Q k v I 1 1 1 1 1 1 INVENTOR WALTER/i VA/VDER WEEL Afrom y v v flq. 2:10.

' Sept. 27, 1960 w. H. VANDER 'WE'E'L METHOD FOR COPYING INDICIA BYPARTICLE TRANSFER FIG. 5

INVENTOR.

WALTER H. 144N051? WEEL BY %A 2, Jam

A/forney United States Patent METHOD FOR COPYING INDICIA BY PARTICLE 5TRANSFER Walter H. Vauder Weel, Ontario, N.Y.

Filed Sept. 25, 1957, Ser. No. 686,242

1 Claim. (Cl. 154-95) This invention relates to a method for rapidlymaking copies of indicia material such as typewritten, pencil, printedor mimeographed indicia and colored indicia such as Water color printsand hectograph copies by subjecting to heat an indicia-bearing sheetwhich is of opaque, translucent or transparent material juxtaposed witha copying sheet to transfer a portion of said indicia adjacent saidindicia material to the surface of the copying sheet by means ofparticle transfer; said copying sheet then being usable for additionalreproductions.

Methods heretofore employed for copying indicia have utilized a thermalcopying paper which when juxtaposed with an indicia bearing sheet andexposed to infrared radiation only reproduced certain types of indicia.For example, methods heretofore have not utilized a copying paper. whichwas capable of reproducing colors and signatures.

Furthermore previous methods for copying indicia utilizing infraredradiation for activation have provided copies of indicia on a copyingsheet but these copies have not been reproducible since the indicia ofthe copies do not absorb the infrared rays, convert them to heat andactivate the copying sheet so that no copies of the first copies areprovided.

It should also be noted that prior methods utilized for making copies ofindicia have been extremely slow and have provided copies of indicia,which have had very poor image clarity.

The present invention relates to a method of rapidly making copies ofindicia material from a sheet bearing indicia by subjecting to heat asheet bearing indicia juxtaposed with 3. copying sheet to reproduce saidindicia material by transferring said indicia material to said copyingsheet to produce indicia on said copying sheet. Colors and signaturesare also reproducible with this method; the copying sheet beingutilizable for additional reproductions.

There have been heretofore proposed a variety of methods for copyingindicia which utilize copying sheets having coatings thereon whichprovide sensitivity to thermal radiations. These methods operate byheating by means of infrared radiation a copying sheet having a coatingcomposed of two react-ants which are light colored disposed in a lightcolored media to cause the reactants to react to provide a dark coloredreaction product. The copying sheet may then be used with any of theknown thermal copying sheets, such as those disclosed in U.S. Patents2,663,654 and 2,663,655, by placing the indicia material of the sheetbearing indicia which is to be copied in contact with the coated surfaceof the thermal copy sheets and exposing to infrared radiation.

Another disadvantage exhibited by previous methods in which heat hasbeen used to cause a copy to be made on a copying sheet has been poorcontrast of indicia to copying sheets due to the color of reactants andreaction products utilized which limits the colors which may be used tothose provided by such reactants and products; for example, a salmoncolored surface after 30 temperature of the backing sheet and highenough not to 7 2,954,311 Patented Sept. 27, 196 0 thermal exposurechanges areas to a blue-grey or dull blue-black. It is desirable toprovide sharp contrast, that is, a jet black or other very dark color onthe areas after heating.

The coating on copying sheets utilized in my method should besufiiciently tacky at temperatures from 150- 350 F. to cause the coatingto adhere firmly to the indicia bearing areas to pick particles from theindicia and form the-desired copy. The coating should also be tackyenough that the copying paper does not slip and provide a blurred copy.However, the coating should not be so tacky at the aforementionedtemperatures that the coating of the copying sheet becomes so firmlyadfixedto the surface of the indicia bearing sheet or the known thermalcopying sheets that the sheets cannot be separated.

It is desirable that copying sheets utilized in the invention be freefrom a tendency to block, i.e., adhere at storage temperatures such as70 to 130 F. and that they be relatively insensitive to pressure fromsharp instruments of the type they are likely to undergo in handling;that is, insensitive to styli, fingernails, staplers, and other officeequipment which may be sharply brought in contact with them.

In accordance with a preferred embodiment of my invention, I utilize acopying sheet which is preferably either a sheet of plasticizedthermoplastic synthetic resin or a sheet of opaque, translucent ortransparent material coated with a thermoplastic synthetic resin, saidresin having a softening temperature below the decomposition be tackybelow F. This copying sheet is juxtaposed in contact with theindicia-carrying side of a sheet bearing indicia which is desired to becopied in such a manner that a resin surface of the copying'sheetcontacts said indicia; the resultant assembly of two sheets is thensubjected to heat or infrared radiation to cause the resin to becomesoftened; particles of the indicia (i.e., dye or pigment particles)adhere to the resin whereby particles from the material being copied aretransferred to the copying sheet. The copying sheet may then beseparated from the sheet bearing indicia thereon and if desired thiscopying sheet may then be used with any of the known thermal copyingsheets, such as those disclosed in U.S. Patents 2,663,654, and2,663,655, by placing the indicia material of the sheet bearing indiciawhich is to be copied in contact with the coated surface of the thermalcopy sheets and exposing to infrared radiation to provide a copy of thefirst copy.

An object of the present invention is a method for copying indicia.

Another object of the invention is a method for copying colored indicia.

-Another object is a method for making a copy of a copy comprisingjuxtaposing a sheet having indicia thereon with a copying sheet of thetype hereinafter described and exposing the assembly to heat to providea copy of the indicia; then juxtaposing the copy of indicia with a knownthermal copying sheet, and exposing the assembly to heat to provide acopy of the first copy.

Another object of the present invention is a method for copying indiciaconsisting essentially of juxtaposing a sheet bearing indicia with acopying sheet consisting essentially of a thermoplastic synthetic resinmaterial or a thermoplastic synthetic resinous coating on a backingsheet and exposing the resultant assembly of two sheets to heat toreproduce the indicia of said indicia bearing sisting essentially of athermoplastic synthetic resinous coating on a backing sheet and exposingthe resultant assembly of two sheets to heat to reproduce the signatureof said signature bearing sheet by transferring a portion of saidsignature on copying sheet to provide a copy of the signature.

Another object is a method for making a permanent copy of indiciaconsisting of juxtaposing a sheet bearing indicia with a copying sheetconsisting essentially of a thermoplastic synthetic resin materiallaminated to a partially heat transparent backing sheet and exposing theresultant assembly of two sheets to heat to reproduce the indicia ofsaid indicia bearing sheet by transferring a portion of said indicia tothe copying sheet to provide a permanent copy of the indicia.

Another object is a method for making a permanent copy of a copycomprising laminating the copy of the indicia of an indicia bearingsheet to a second sheet having a color contrasted with the color of saidindicia of said copy to produce a permanent copy of said indicia.

Other objects will become apparent from the drawings and from thefollowing detailed description in which it is intended to illustrate theapplicability of the invention without thereby limiting it to scope lessthan that of all equivalents which will be apparent to one skilled inthe art; in the figures, like reference numerals refer to like partsand:

Figure 1 is a cross-sectional view of a method of the invention;

' Figure 2 is a cross-sectional view of a method of the invention;

Figure 3 is a cross-sectional View of a method of the invention;

Figure 4 is a cross-sectional view of a method of the invention;

Figure 5 is a cross-sectional View of the assembly before treatment inaccordance with the method of the invention;

Figure 6 is a cross-sectional view of the copy produced by the method ofthe invention; and

Figure 7 is a cross-sectional view of the original indicia bearing sheetafter treatment in accordance with the method of the invention.

Referring now to the drawings, there is shown in Figure 1 a method forcopying indicia comprising juxtaposing a copying sheet 2 consisting of aheat transparent backing-sheet 3 which may be opaque, transparent ortranslucent, synthetic organic resin having coated thereon a coating 4of thermoplastic synthetic resin, with the indicia 5 of an indiciabearing sheet 6 which may be opaque, translucent or transparent, andsubjecting the resultant assembly to heat from a source located above orbelow the assembly, said source located above the assembly for the sakeof simplicity being designated as 7, said source located below theassembly for the sake of simplicity being designated as 7. The heatsoftens coating 4 causing the coating to become tacky and causingtransfer of a portion of particles from indicia 5 adjacent the indiciabearing areas to the tacky surface on sheet 2 to provide indicia 8thereon, thus providing a copy sheet having indicia thereon.

The method of Figure 3 is the same as Figure l but utilizes a copyingsheet 12 consisting of a synthetic resin which may be opaque,transparent or translucent.

The heating for Figures 1 and 3 may be accomplished by subjecting theassembly comprising an indicia-bearing sheet 6 juxtaposed in contactwith copying sheet 2, 12 to a source of heat 7 located above theassembly so the heat passes downward thru the assembly to heat thecopying sheet as a whole by means of conduction thus softening thecopying sheet and causing it to become tacky to transfer the indiciafrom the indicia bearing sheet to the copying sheet.

Heating for Figures 1 and 3 may also be accomplished by subjecting theassembly comprising indicia-bearing sheet 6 juxtaposed in contact withcopying sheet 2 or 12 to a source of heat 7 located below the assemblyso the heat passes upward thru the assembly heating the copying sheet 2,12 by convection until the copying sheet is softened and tacky to causetransfer of indicia 8 adjacent the indicia 5 of the indicia-bearingsheet 6 to the softened copying sheet 2, 12.

Heating for the methods of Figures 1 and 3 may also be accomplished bypassing infrared radiation down thru the assembly shown in Figures 1 and3, the majority of the rays from the radiation being absorbed by thepigment in the coating or by the pigment in the copying sheet 12 andconverted to sensible heat to soften the coating 4 or copying sheet 12to transfer a portion of the indicia 5 adjacent the indicia bearingareas to the tacky surface on copying sheet 2, or 12.

It is preferable that this means of heating i.e., infrared radiation notbe employed for. the method of Figure 1 or if dyes are employed in thecopying sheet 12 or coating 4 since optimum results are not obtained dueto preferential heating in the indicia bearing areas.

Figure 2 shows the'copying sheet 2 having heat absorbent indicia 8thereon as producedby the method of Figure 1 juxtaposed with a heatsensitive copying paper sheet 9 of the type described in US. Patents2,663,654, 2,663,- 655 and copending application Ser. No. 644,541. Thetwo sheets thus disposed are exposed to heat from a source of heatlocated above the assembly; said'source of heat indicated generally as 7to provide copying sheet 9 with indicia 8. I

The method of Figure 4 is the same as the method of Figure 2 except thatit utilizes the activated copying sheet of Figure 3 having indicia 8thereon.

The necessary heating for the methods of Figures 2 and 4 may be producedbypassing infrared radiation indicated generally as 7 down through theassembly of copying sheet 2, 12 bearing indicia 8, 8 and known thermalcopying sheet 9, the maximum number of rays from the radiation areabsorbed by the indicia 8, 8 of the indicia bearing copying sheet 2, 12and are converted to sensible heat to soften the copying sheet and causethe surface to become tacky to cause transfer of a portion of theindicia 8, 8' adjacent the indicia bearing areas to the known thermalcopying sheet 9.

Figure 5 shows copying sheet 2 consisting of a partially heattransparent backing sheet 3 and coating 4 juxtaposed with indicia 5 ofan indicia bearing sheet 6 before treatment in accordance with themethod of the invention.

Figure 6 shows copying sheet 2 consisting of a partially heattransparent backing sheet 3 and coating 4 with indicia 8 thereon aftertreatment in accordance with the ethod of the invention.

Figure 7 shows the original indicia 5 of the indicia bearing sheet 6after treatment in accordance with the method of the invention, showingthat portion of indicia 5 which was transferred to the copying sheet.

Suitable means is described in such patents as US. Patents 2,663,655 and2,740,895 for reflecting infrared radiations from a highly heated rod orfilament against a portion of both the copying sheet and the indiciabearing sheet while the sheets are passed over the rod or fila-. ments,being held in place between a belt of heat resistant synthetic resin,such as, for example, polychlorotrifluoroethylene, and suitable holdingmeans.

Printing by themethod of the invention may be accomplished in anysuitable manner; a preferred manner is to utilize a machine or anysuitable device which can produce thenecessary amount of heat; theamount of heat needed being suflicient tosoften the thermoplasticsynthetic resin film but not so great as to melt the thermoplasticsynthetic film and cause apertures therein. General heating of theassembly comprising indicia bearing sheet and copying sheet as a wholeis preferred to preferential heating in the indicia bearing areas.

Under certain conditions preferential heating in the indicia bearingareas may occur due to the presence of a pigment in the copying sheetbut this is not desirable since it does not give optimum results.Heating of the sheet is preferably at a temperature of from 150 F. to350 F.

By copying sheet utilizable-in my method, I mean a copying sheetcomprisingthermoplastic synthetic resin sheets or films orbacking-sheets which are opaque ortransparent coated with thermoplasticsynthetic organic resinous materials which when subjected to atemperature from 150 F. to 350 F. will soften sufiiciently to allowparticles from the indicia material, i.e., dye or pigment of the indiciabearingsheet to be picked up to provide acopy of the indicia.- I r I Bythermal copying sheets, I mean copying sheets of the type described inUS 2,663,654, 2,663,655, and copending application Ser.'No. 644,541which when used with the copying sheet having indicia thereon willproduce additional copies-on exposure to infrared radiation.

While a variety of synthetic organic resin sheets or films may beutilized to provide a copying sheetor the coating on the copying sheetsuitable for my method, thermoplastic synthetic organic resinousmaterials are generally preferred.

A copying sheet suitable for my method is preferably a non-tacky opaqueor transparent thermoplastic resin which is subjected to a minimum ofheat distortion and which on subjecting to heat is capable of particletransfer of the particles from the indicia bearing sheet to the copyingsheet.

A copying sheet suitable for use may be a white sheet or any color, evenblack; the color preferably but not necessarily contrasted with thecolor of the indicia which is to be copied. i The thermoplastic materialwhich is preferred is cellulose triacetate. However, suitable resultshave also been obtained with vinyl compounds such as polyvinyl acetate,polyvinyl chloride, polyvinylidene chloride and copolymers therewith,polyvinyl butyral, styrene and its homologs, polyamides, acrylates andmethacrylates or the like.

A preferred synthetic resin for the coating is a natural latex orlatex-like composition, i.e., an emulsion cornprising an elastomeric orother polymeric synthetic resin which is preferably thermoplastic innature. It may be necessary to adjust the materials to provide propertack. Such apolymeric resin-may be polyvinyl chloride, polyvinylalcohol, polyethylene, polyvinyl acetate, copolymer of vinyl acetate andvinyl chloride, halogenated polyethylene, halogenated rubb'er,hydrochlorinated rubber, natural rubber, i.e., polyisoprene,polychloroprene, polybutadiene, copolymer of any one of the last threewith styrene and/or acrylonitrile, or other monomer adapted to undergopolymerization through ethylenic unsaturation. A suitable plasticizermay be included. i

A particularly suitable coating'composition has been found to be amixture of low viscosity and low molecular weight polyvinyl acetate andchlorinated rubber dissolved in a suitable solvent such as toluene. Thiscomposition may be suitably coated on cellulose triacetate and gives aparticularly suitable copying sheet used in my method 6 and the otherside of the roll running against a web of paper or other sheet material.After passing over the roll, the web is then passed over a Mayerequalizer rod consisting of a rod of about one quarter inch diameterwound with wire in the form of a tight coil or helix, the wire beingpreferably No. 6 wire.

Tackifying agents which may be used when the thermoplastic coating doesnot have a suitable tack of its own include: Pliolite (a naturalrubber-stwene copolymer produced by Goodyear) resins, alkyd resins andlatices as well as other tackifying agents.

The coating of synthetic organic resinous material on the copying sheetutilized in my method may be clear, i.e., transparent or translucent, orit may be colored by the addition of coloring material. As a coloringagent or coloring material to be included, there may be used either apigment or a dye; a pigment absorbs a relatively largeportion ofinfrared rays and converts such rays into heat whereas a dye transmits alarge portion of infrared rays and absorbs and converts a minimum ofsuch rays into sensible heat. I

If the copying sheet utilized in mymethods is to be reproduced withknown thermal copy sheets, it is desirable that the coloring agent orcoloring material to be included with the resin coating be a materialwhich transmits a relatively large portion of infrared rays and whichabsorbs and converts substantially a minimum of such rays into sensibleheat.

The extent of exposure to infrared radiation used in my method dependson the coloring matter employed in the copying sheet. When a smallamount of pigment is present in the copying sheet, relatively few raysare absorbed and converted to sensible heat so that a long exposure timemust be employed to soften the copying sheet sufficiently to obtainparticle transfer thereto. However, if a large amount of pigment isused, a greater portion of rays are absorbed and converted to sensibleheat and only because of its aging characteristics, i.e., didntdeteriorate during storage.

The formulation for the coating may be coated on a suitable supportmaterial by any suitable means; from a-solvent for example, in the caseof materials for templates wherein the coating is to be applied toaluminum or steel sheet, it may be applied with a brush or by sprayingor dipping. Preferably ,it is applied by means of a suitable coatingtechnique for obtaining a thin coating of relatively uniform thicknessusing standard coating equipment such as a knife coater reverse roll'coater, or the like. It is particularly suitable to coat with;atransfer roll which operates with one side of the roll dipping into apan ofthe material to be coated a short exposure period is necessary. Iflarge concentrations of dyes are used, however, a greater portion ofrays will be transmitted, thru the assembly but some rays will beabsorbed and converted to sensible heat. In order to get sufficient heatto obtain particle transfer, a very long exposure would be needed.

Suitable dyes which may be utilized include, for example, for a greencolor, a mixture of 10% Iosol Yellow (National Aniline Company) plus ofVictoria Blue, BOC, as sold by Du Pont, or Victoria Blue base, as soldby Du Pont. There may also be used Crystal Violet, as sold by NationalAniline Company. To provide a dark red color there may be suitably usedRhodamine B-base as sold by Du Pont.

I may provide "a plurality of colors so that various colors may be usedfor various purposes by ultimate users to indicate, for example, thetype of materials which have been copied or locations in which morecopies would be filed, or other information.

In order to improve the adhesion of the thermoplastic coating to thebacking sheet, there may be added to the formulation thereof from 1-3%of a relatively tacky material such as alkyd resins or modified resinester or I'OSIH.

A preferred synthetic organic resinous backing sheet may be eitheropaque or translucent or transparent to visual rays and infrared rays,has a surface capable of providing good adhesion to coatings and isdevoid of irregularities in thickness. The thickness of the backingsheet depends on the thermoplastic material used and its transparency toheat as well as other factors.

The backing sheet may be any fibrous or regenerated cellulose or anycontinuous film. Materials which are suitable include: cellulose esterssuch as cellulose acetate and cellulose butyrate, cellulose t-riacetate,styrene and its derivatives, vinyl polymers such as vinyl chloride,vinylidine chloride or copolymers thereof, polyvinyl acetate such aspolyvinyl butyral, vinyl acetate, polyvinyl alcohol,

'3' Mylar (a polyester film produced by the Du Pont Company), Tygontaseries of compounded, modified, halide polymers, condensation resins anddiene derivatives produced by US. Stoneware), nylon or any otherfilm-former which is relatively transparent to heat.

A preferred fibrous material for a backing sheet is an opaque materialwhich is partially transparent to heat, has a rough surface to providegood adhesion to coatings and has excellent uniformity of fiberstructure and is devoid of fiber and filler irregularities which tend tocause graininess in an image. Suitable papers include a .019", 13 lb.(per 500 sheets of 20 x 30 inch size) milo paper produced by S. D.Warren Company, Portland, Maine; a .020", 15 lb. (per 500 sheets of x 20inch size) white milo paper produced by the same company; and a .015",lb. (per 500 sheets of 24 x 36 inch size) white greaseproof paper madeby the Riegel Paper Company.

TEE backing sheet when opaque furnishes a negative copy and copies maybe made therefrom according to my method, however if the backing sheetis translucent or transparent the copy may be read from the back.

The indicia-bearing sheets which are applicable for copying inaccordance with my method include opaque, transparent and translucentsheets having indica thereon. Materials such as photographic prints andstencils carrying visually unobservable indicia or apertured indicia arenot suitable for copying.

The preferred method for making copies of indicia is juxtaposing a sheethaving indicia thereon with either a plasticized thermoplastic syntheticresin or a thermoplastic synthetic resin coating on a backing sheet,said resin having a non-tacky surface at temperatures below 100 F. andhaving a softening point from 150 F. to 350 F. followed by exposing theresultant body to heat to form a copy of the indicia.

Another method comprises a dark colored copying sheet juxtaposed with asheet having indicia thereon, followed by exposure to a temperaturebetween 150 F. to 350 F. This activated colored copying sheet, while itis unreadable, may be used as a negative for additional reproductions.The activated copying sheets may have serial numbers placed thereon, sothat a chronological file could be set up to hold the negatives, thisbeing suitable where a complete chronological file of all correspondenceis desired.

The invention is further illustrated by the following examples whichillustrate certain embodiments but are not to be taken as limiting theinvention only to those particular embodiments illustrated, it beingunderstood that other embodiments and equivalents will be apparent tothose skilled in the art.

Example 1 A coating having the following formulation:

1 part by weight polyvinyl chloride resin (prepared by Borden) 4 partsby \veightmethyl ethyl ketone .1 part by weight Unidol 40 .4 part byweight Pliolite 8-5 (a viscosity improver for coatings, a thermoplasticcopolymer produced by Goodyear) is mixed and coated on a cellulosetr-iacetate sheet .002" thick using a Mayer equalizer rod to provide acoating layer having a thickness of about .004, then dried. Copyingsheets are then cut out. One of the copying sheets utilizable in mymethod is then laid against printed sheets and exposed for about 20seconds at 180 F. This heat causes the coating to become 'tacky and thecoating then picks .up particles from the indicia of the printed sheet.Excellent copies of the original are obtained.

Example 2 A coating having the following formulation:

1 part by weight Vinac B75 (a polyvinyl acetate produced by the ColtonChemical Company.)

1 part Parlon, 20 cps.

23 parts by weight acetone 23 parts by weight of toluene Example 3 Asheet of cellulose acetate .015" thick is rod coated with RX70 Blueadhesive (a rubber base adhesive produced by Industrial Latex Company)to a 3 mil wet thickness coating over the cellulose acetate sheet. TheRX70 Blue adhesive is then coated with a 1-2 mil thickness coating ofVinac B15 (a polyvinyl acetate produced by the Colton Chemical Company).The resulting sheet is then juxtaposed with an indicia bearing sheet andthe resultant assembly exposed to heat to soften the coating until itbecomes tacky and picks up particles from the indicia to give a bluecopying sheet having a copy of the indicia of the indicia bearing sheetthereon,

Example 4 A coating having the following formulation:

is mixed and coated on a cellulose triacetate sheet .01" thick with atransfer roll and Mayer equalizer rod dried and stored one week. Theresultant sheet is then laid against a typewritten sheet and exposed for5 seconds at 170 F. to provide a copy of the typewritten sheet.

Example 5 A coating having the following formulation:

2.1 grams Vinac B7 in a 57% solution of acetone (Vinac B-7, a lowviscosity and low molecular weight poly vinyl acetate produced by theColton Chemical Com- P m) 3.2 grams of Parlon, 20 cps., in a 58%solution toluol (Parlon, Q0 cps., a chlorinated rubber produced byHercules Chemical Company) 2.0 grams tricresyl phosphate is brushed on a3 mil cellulose triacetate sheet and air dried. The coated copying sheetthus obtained is laid against a typewritten sheet having pencilnotations thereon, exposed for 10 seconds at 205 F. The heat softens thecoating until it becomes tacky and picks up particles from the type andthe pencil notations to produce a copy of the sheet which is to becopied.

Example 6 A polyvinyl alcohol film sheet 3 mils thick is laid against atypewritten sheet and exposed for 20 seconds at F. The heat causes thefilm to soften until it becomes tacky and picks up a portion of theindicia particles from the original to provide a copying sheet havingclear indicia contrasting to the color :of the copying sheet. Theactivated copying sheet may'then be laminated to a partially heattransparent backing sheet to provide a permanent copy of saidaetivatedcopy sheet.

Example-7 j The composition of Example is coated on a web of 16 poundwhite milo paper as hereinbefore described to provide a coating .003"thick when wet and is then dried. The copying sheet thus obtained isthen juxtaposed with an indicia bearing sheet and the. resultantassembly exposed to heat to provide a copy of the indicia.

Example 8 The composition of Example 1 is coated on 16 pound white milopaper as hereinbefore described to provide a coating .5 thick. Thecoating on the copying sheet is then dried. The copying sheet thusobtained is juxtaposed with the indicia of an indicia bearing sheet andexposed to heat to provide a copy of the indicia on the copying sheet.This copying sheet can be utilized for additional reproductions if theoriginal has to be returned and additional copies are needed.

Example 9 The composition of Example 4 is coated on a 4 coloredregenerated cellulose film sheet to give acoating .015" thick and afterair drying the resultant sheet is laid against a typewritten sheet to becopied and exposed for 15 seconds at 180 F. to provide a copy of thetypewritten indicia.

Example 10 The activated copying sheet of Example 4 is laid against aheat-sensitive copying paper as disclosed in U.S. Patent 2,663,655. Theresultant body is exposed to radiant energy and a copy of a copy isthereby provided.

Example 11 up particles from the indicia of the letter to provide anexcellent copy of the original.

Example 12 The coating composition of Example 5 is applied to apolyvinyl alcohol film sheet until the coating is .004" thick and thenis allowed to air dry. The resultant coated sheet is cut to provide acopying sheet. One of the aforementioned copying sheets is laid againsta typewritten letter, said letter being typed on stationery having greenletterhead and the resultant assembly 15 then exposed to a temperatureof 200 F. for 12 seconds. The coating composition softened and picked upthe particles from the indicia on the stationery to provide a copy ofnot only the typewritten indicia but also the green letterhead.

Example 13 The coating composition of Example 1 is applied to a Mylarfilm sheet to provide a coating .0025 thick and then air dried. Theresultant coated sheet is cut to provide copying sheets. One of theaforementioned copying sheets is laid against a mimeographed page havingnotations in blue ink thereon and then exposed to a temperature of 195F. for 15 seconds. The coating composition softened, suficiently tobecome tacky and picked up the particles from the indicia on themimeographed page juxtaposed'therewith and'also picked up blue 0136ticles from the-notations written in blue ink'thereomto provide aduplicate copy of the original. This activated copying sheet is thenjuxtaposed with a thermal copying sheet as is described in U.S. Patent2,663,654 and exposed to radiant energy to produce a copy of theheat-absorbent indicia of the original.

r 0 Example 14 The activated copying sheet of Example 5 is placedagainst a heat sensitive copying paper of the type de-' scribed in mycopending application Serial No. 644,541 and is exposed to radiantenergy to provide an exact duplicate to the original described inExample 5.

Example 15 The activated copying sheet of Example 8 is placed against aheat sensitive copying paper as disclosed in U.S. Patent 2,663,654 andis exposed to a temperature of 250 F. for 5 seconds to provide anexcellent copy of the original indicia.

Example 16 The activated copy sheet of Example 11 is placed against aheat sensitive copying paper of the type described in U.S. Patent2,668,126 and is exposed to radiant energy to provide a duplicate ofheat absorbent indicia described in Example 11.

Example 17 Example 18 A polyvinyl alcohol film sheet 1 mil thick islaminated to a partially heat transparent backing sheet of 16 poundwhite milo paper as hereinbefore described and the resultant laminatelaid against the type of a typewritten sheet and exposed for 20 secondsat F. The heat causes the film to soften until it becomes tacky andpicks up a portion of the type from the type of original typewrittensheet to provide a permanent copying sheet having indicia contrasted tothe color of the backing sheet.

Particular advantages of the method of my invention are (1) colors maybe reproduced from originals, (2) both heat sources and radiant energymay be employed for activation, (3) good contrast of indicia tobackground may be obtained, (4) short exposure periods may be used toproduce excellent copies, and (5) the copy sheet utilized, afteractivation, may be used with known thermal copying sheets to produceadditional copies; the latter being especially advantageous when theoriginal has been returned and additional copies are required.

It should also be noted that the method of. my invention is capable ofreproducing signatures, of which methods heretofore have not beencapable. This fact is especially noteworthy since it has not beenpossible to make exact reproductions of complete letters, even includingsignatures.

It may thus be seen that the invention is broad in scope and includessuch modifications as will be apparent to those skilled in the art andis to be limited only by the claim.

Having thus described my invention, I claim:

A method for copying relatively non infra-red absorptive indiciacomprising providing an indicia bearing sheet wherein indicia on saidsheet are substantially as non infra-red absorptive as such sheet andjuxtaposing incontact with said indicia a second sheet comprising a filmof flexible fold-able synthetic organic resin, subjecting the thusprovided assembly of two sheets to infrared radiation so that at leastaportion ofsaid radiation is absorbed by at least one of said sheets tosoften said second sheet and cause atleast a portionof-said indicia toadhere to said second sheet and then causing said assembly to cool untilsaid second sheet has lost said softening and then separating saidsheets to complete the transfer of a portion of said indicia fromsaidfirst sheet to said "References-Cited in the file of this patent UNITEDSTATES PATENTS 2,501, 9 Car o et Mar- 21 5 2,715,363 Hoover Aug. 16 19552,721,821 Hoover Oct. 25, 1955 2,740,896 Miller Apr. 3, 1956 2,808,777Roshkind Oct. ,8, 1957

